The long-term objective of the project is to identify environmental demands and individual capabilities that affect the cognitive functioning of older adults in natural contexts. The premise of this application is that age differences in cognitive functioning are mediated by task constraints and individual differences. Thus, the proposed studies are organized around the specific aims of examining age differences in decision-making performance and strategy-use within the context of task demands and the individual's experiences and capabilities. Information processing theory and prior research in the task-relevant decision-making performance of younger adults provide a foundation for the proposed studies. Maintaining the functioning of older adults depends on examining the conditions under which older adults function without intervention in order to define needs for interventions. The health relatedness of the project is that it specifies strategies older adults use to reduce the impact of agerelated declines in basic cognitive processes, such as memory, in order to optimize day-to-day functioning of more complex cognitive processes, such as making decisions. Specific hypotheses examine differences in the decision making performance of healthy adults between 18 and 35 years and between 60 and 85 years of age within the context of task demands and individual differences. Experimental conditions will manipulate task instructions, incomplete information, and inconsistent information, as well as compare individuals varying in sophistication of their decision-relevant knowledge structures. Dependent variables are: total time to decision, amount of information considered, time per piece of information, sequence of information acquisition, variation of information searched across alternatives' final choice, and recall of information. The effortful nature of decision-making strategies is deduced from measures of the sequence and variation of information searched. Additional measures will provide correlational data on education, vocabulary skills, analogical reasoning skills, current mood state, and meta-cognitive beliefs, working memory capacity and abilities. The research plan also includes secondary data analysis and meta-analysis of age-by-task interactions and of effects due to age after controlling for individual differences in order to examine the combined findings of the preliminary and proposed studies.